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W. Jason Morgan: Geophysics
guru honored

Jason Morgan received
an unexpected phone call from the National Science Foundation in October. I
thought they were calling because one of my project reports was late,
he says with a grin, while seated on a couch at the Ritz-Carlton in Washington,
D.C., two weeks later. After waiting uneasily on hold, Morgan was told the stunning
news that he was the recipient of the National Medal of Science, an award for
lifetime achievement.
Jason Morgan, the day after receiving the National Medal of Science for his
contributions to the plate tectonics revolution. Photo by Naomi Lubick.

The Princeton professor, who will retire in February, is considered by many
to be the key architect of plate tectonic mechanics. He was first to publicly
present a global view of how all the plates move with regard to each other.
Two years later, he wrote another more controversial idea paper, proposing a
plume-fed model of mid-plate hotspots.

With the first paper, he hit a grand-slam home run, says Seth Stein,
at Northwestern University in Evanston, Ill. Decades later, space-based observations
with GPS match the models predicted plate motions beautifully,
he says. Steins own research builds on the framework Morgan put forward
in his American Geological Union (AGU) talk, Rises, Trenches, Great Faults
and Crustal Blocks, which Morgan later published in 1968 in the Journal
of Geophysical Research.

The 1960s had tremendous opportunity for anyone with a background
in mathematics and geophysics, says Naomi Oreskes, a science historian at the
University of California at San Diego. Navy funding sponsored the collection
of masses of undigested data over the previous two decades, she
says, a motherlode waiting to be tapped.

At the time, Morgan was a post-doctoral fellow at Princeton University, in Princeton,
N.J. Though Morgan had intended to be an engineer when he entered college at
Georgia Tech in Atlanta, he became interested in physics and celestial bodies
instead, and joined Robert Dickes group as a modeler. Dickes approach
to science questioned certain assumptions, Morgan says, a tactic
he himself internalized.

Intending to talk about magnetic anomalies and mantle properties beneath the
Puerto Rico trench, Morgan submitted an abstract for the 1967 AGU meeting. But
several months before the meeting, he read a paper by Bill Menard of Scripps
Institution of Oceanography in San Diego, who described how only one of the
massive fracture zones on the Pacific seafloor follows the Great Arcs of the
Earths sphere  and the rest splay every which way.

A pattern jumped out at Morgan, who says he recognized it from maps he saw while
in the Navy in the late 1950s. Menards map outlined fractures that seemed
to fit concentric circles around a pole, something Morgan immediately set to
testing, hammering out a model within a month.

To fit current continental drift ideas, geoscientists thought the crust was
deformable, Morgan says. But his model of plate boundaries showed that the plates
themselves behaved like rigid bodies on a sphere, rotating around Euler poles.
That the whole plate was strong was a surprise, Morgan says, with
immense geologic implications.

The talk Morgan was to give on gravity anomalies in the Puerto Rico trench no
longer interested him. Instead, half an hour after he was scheduled to talk,
after most of the researchers had left for lunch, Morgan presented his model
on how Earths plates move. He recalls only Xavier Le Pichon in the audience,
with Bill Menard as chair.

Several months after that presentation, Dan McKenzie (now at the University
of Cambridge) and Robert Parker, both at Scripps at the time, published a very
similar idea in Nature, before Morgan could publish his paper. The evidence
is clear, Oreskes says, that they were working independently on the same problem,
which is common in science, she says. When a problem comes
up, you get to work on it.

Sean Solomon, head of the Department of Terrestrial Magnetism at the Carnegie
Institution of Washington, calls Morgans 1968 article the single
most important paper in solid earth sciences in the last century. Morgans
second paper  in which he named the source of hotspots plumes
for the first time  was almost as influential, Solomon says,
if more controversial because he hypothesized they may be rooted deep in the
mantle. Jason has exceptionally broad understanding, Solomon says.
He does not restrict himself to any one discipline.

Jason Phipps Morgan, Morgans son and a current collaborator, says his
fathers generalist tendencies make working with him stimulating.
Marcia McNutt, a geophysicist who heads the Monterey Bay Aquarium Research Institute
in Moss Landing, Calif., has worked only with the younger Morgan. What
strikes me most, she says, is the elder Morgans ability to
connect things in a very quantitative way, connecting observation to theory.

Morgan is one of about 15 geoscientists to receive the National Medal of Science
since the honors were first bestowed in 1959. Nodding and smiling, Morgan leans
back on the hotel couch the day after the Nov. 6 ceremony at the White House,
and says, I was very lucky.